Home Civil Engineering Waste and Water Engineering Important MCQs

Waste and Water Engineering Important MCQs

1 - ¾th or ¼th extra space is left in sewer pipes at maximum discharge for_________________?

All the above

2 - 15 cumecs, the depth d and width are related by For drains up to___________________?

d = 0.5 B

3 - 3.0 ml of raw sewage is diluted to 300 ml. The D.O. concentration of the diluted sample at the beginning of the test was 8 mg/l. After 5 day-incubation at 20°C, the D.O. concentration was 5 mg/l. The BOD of raw sewerage is______________________?

300 mg/l

4 - 5 days-biochemical oxygen demand (BOD5) is taken at a temperature of_________________?

20°C

5 - A 70% index of wetness means_______________?

rain deficiency of 30%

6 - A circular sewer section is preferred to because__________________?

All the above

7 - A current meter is used to measure the__________________?

velocity of flow of water

8 - A cylindrical ejector having its height 2 m fills after every 10 minutes with a peak sewage discharge of 0.0157 cumec. The diameter of the ejector chamber, is_____________________?

2.45 m

9 - A deep well_________________?

has more discharge than a shallow well

10 - A divide wall is provided_______________?

at right angle to the axis of weir

11 - A drop manhole is provided if__________________?

A branch sewer joins the main sewer at higher level

12 - A hydroelectric scheme operating under a head of 80 m will be classified as_____________?

high head scheme

13 - A manhole is classified as shallow if its depth is between_________________?

0.7 to 0.9 m

14 - A manhole is generally provided at each__________________?

All the above

15 - A nuisance is experienced in diluting water if dilution factor is less than_________________?

20

16 - A rain sanitary sewer is constructed to carry_________________ ?

Sanitary sewage

17 - A rainfall may be classified as acidic if its pH value is less or equal to________________?

5

18 - A raingauge should preferably be fixed________________?

in an open space

19 - A river training work is generally required when the river is_______________?

meandering type

20 - A safety lamp when inserted in the upper portion of a manhole causes flames. It indicates the presence of______________?

Methane gas

21 - A sewer pipe contains 1 mm sand particles of specific gravity 2.65 and 5 mm organic particles of specific gravity 1.2, the minimum velocity required for removing the sewerage, is_____________________?

0.45 m/sec

22 - A sewer running partially full and hurried with back filled, fails in compression due to_________________?

All the above

23 - A straight glacis type fall with a baffle platform and a baffle wall is called_____________?

inglis fall

24 - A unit hydro graph has one unit of_______________?

rainfall excess

25 - A well oxidized sewage contains nitrogen mainly as___________________?

Nitrates

26 - According to Khosla's theory, the exit gradient in the absence of a downstream cutoff is_____________?

infinity

27 - Aeration of water is done to remove______________?

odour

28 - Aerobic activity is maximum_______________?

In freshly produced sewage

29 - Aerobic bacterias___________________?

All the above

30 - An aggrading river is a_________________?

silting river

31 - An artesian aquifer is the one where______________?

water is under pressure between two impervious strata

32 - An inverted siphon is designed generally for____________________?

Three pipes

33 - are available in size Stoneware sewers________________?

All the above

34 - As compared to crest of the normal portion of the weir, the crest of the under sluice portion of weir is kept at_____________?

lower level

35 - As compared to fresh river water, sea water contains oxygen_________________?

20% less

36 - As compared to gravity dams, earthen dams__________________?

require less skilled labour

37 - As per IS : 1172-1963, water required per head per day for average domestic purposes, is_______________?

135 litres

38 - As per Lacey's theory, the silt factor is_________________?

directly proportional to square root of average particle size

39 - Asbestos pipes are ______________?

all the above

40 - Assertion A : To estimate the rainfall over a catchment, the number of raingauges required per unit area is large for hilly areas. Reason R : Rainfall gradient is steep. Select your correct answer according to the coding system given below ?

Both A and R are true and R is the correct explanation of A

41 - Assertion A. : Discharging the effluents from the oxidation ponds just up stream of lakes or reservoirs is undesirable. Reason (R) : The discharged algae get settled in the reservoirs and cause anaerobic decomposition and other water qualities____________

Both A and R are true and R is the correct explanation of A

42 - Assertion A.: A free board of 0.3 m is provided above the top sewage line in septic tanks. Reason (R): It helps to accommodate the scum in the septic tank_________________?

Both A and R is true and R is the correct explanation of A

43 - Assertion A.: The determination of pH value of sewerage is important. Reason (R): The efficiency of certain treatment methods depends upon the availability of pH value________________?

Both A and R are true and R is the correct explanation of A

44 - Assertion A.: The minimum self cleansing velocity in the sewer, at least once a day, must be generated. Reason (R): If certain deposition takes place and is not removed, it obstructs free flow and causes further deposition leading to complete blocking of

Both A and R are true and R is the correct explanation of A

45 - At the junction of sewers___________________?

None of these

46 - Average annual rainfall at any station is the average of annual rainfall over a period of________________?

5 years

47 - Before discharging the foul sewage into rivers, it is generally treated by_____________________?

All the above

48 - Biochemical Oxygen Demand (B.O.D.) of safe drinking water must be________________?

nil

49 - Bio-chemical oxygen demand (BOD) for the first 20 days in generally referred to_______________?

All of these

50 - Boussinesq's equation for ascertaining unit pressure at a depth on sewers due to traffic loads, is__________________?

pt = 3H3p/2 Z5

51 - By boiling water, hardness can be removed if it is due to_________________?

calcium bicarbonate

52 - Cement concrete sewers are only suitable if non-scouring velocity is between_________________?

2.5 to 3.0 m/sec

53 - Chlorination of water is done for the removal of____________________?

Bacterias

54 - Clogging of sewers, is caused due to_______________?

All the above

55 - Coefficient of discharge of an ogee spillway________________?

both (A) and (B)

56 - 'Cowl' is provided at___________________?

Upper end of ventilating column

57 - Cyclonic precipitation is caused by lifting of an air mass due to________________?

pressure difference

58 - Depletion of ozone layer in the outer atmosphere may cause___________________ ?

Skin cancer

59 - Design period of 40 to 50 years is adopted for_________________?

All the above

60 - Dilution method of disposing of sewage, is not preferred to_______________?

When diluting water is used for water supply near the point of sewage disposed

61 - Dimensions of coefficient of transmissibility are______________?

M° L2 T1

62 - Discrete or granular particles change their_________________ ?

None of these

63 - Disinfection of drinking water, is done to remove_________________?

bacterias

64 - Disposal to sewage in large cities, is done in__________________?

Dilution

65 - Drop manholes are the manholes___________________?

Having drains at different levels

66 - Drop manholes at the junctions of sewer lines, are provided if________________?

Invert level of a branch sewer is more than 60 cm that of the main sewer

67 - Dry water flow in a combined sewer, is______________________?

Storm water

68 - Dry weather flow is__________________?

Water supply allowance per capita

69 - During purification process of sewage the gas given off, is________________?

All the above

70 - Facultative bacteria survive in_____________________?

Both cases A. and B.

71 - Flocculated particles do not change their___________________?

None of these

72 - For a catchment area of 120 km2, the equilibrium discharge in m3/hour of an S-curve obtained by the summation of 6 hour unit hydro graph is_______________?

0.2 x 106

73 - For a flood control reservoir, the effective storage is equal to_______________?

useful storage + surcharge storage -valley storage

74 - For a grit chamber, if the recommended velocity of flow is 0.2 m/sec and detention period is 2 minutes, the length of the tank, is__________________?

24 m

75 - For a peak discharge of 0.0157 cumec, with a velocity of 0.9 m/sec, the diameter of the sewer main, is________________?

15 cm

76 - For a proportional outlet, the flexibility is______________?

1

77 - For an annual flood series arranged in descending order of magnitude, the return for a magnitude listed at position period m in a total data N is________________?

(N+l)/m

78 - For design of sewers, percentage of sewage discharge is assumed_____________________?

75 to 80%

79 - For design purposes, the normal rate of infiltration of ground water into the sewer, is___________________?

2000 litres/km/cm

80 - For detecting the nitrates in sewage, the colour may be developed by adding________________?

Phenol-di -sulphuric acid and potassium hydroxide

81 - For detecting the nitrites in the sewage, the matching colour may be developed by adding_________________?

Sulphuric acid and napthamine

82 - For estimating the peak run off the rational formula Q = 0.0278 KpA was evolved by______________?

All the above

83 - For evaporation and measurement of settable solids, the apparatus used, is________________?

An Imhoff cone

84 - For house drainage minimum gradient is__________________?

1 in 60

85 - For large sewers, maximum distance between manholes may be_______________?

300 m

86 - For laying a sewer line in a trench of 2 m width, an offset line is marked on the ground parallel to the given centre line at a distance of___________________?

160 cm

87 - For non-scouring velocity 5 m/sec, the type of sewers generally preferred to, is____________________?

Glazed bricks sewers

88 - For sewer mains of 0.5 to 1 m diameter, the ratio of maximum daily sewage flow to the average daily sewage flow is assumed__________________?

2

89 - For sewers, inverted siphon is provided for___________________?

Three pipes

90 - For supplying water to rabi crop, kharif crop and sugarcane, the channel is designed for a capacity equal to the greater of the water requirement of_______________?

rabi and sugarcane or kharif and sugarcane

91 - For the COD test of sewage, organic matter is oxidised by K2Cr2O7 in the presence of________________?

H2SO4

92 - For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed________________?

4 ppm

93 - For the upstream face of an earthen dam, the most adverse condition for stability of slope is_______________?

sudden drawdown

94 - For treating the sewage of a large city, you will recommend_________________?

A sedimentation tank and an activated sludge treatment plant

95 - For trunk and out-fall, the type of sewers generally used, is_____________________?

Horse shoe shaped

96 - For trunk sewers more than 1.25 m in diameter, the ratio of the maximum daily sewage flow to the average daily sewage flow is assumed________________?

1.5

97 - For wave action in dams, the maximum height of freeboard is generally taken to be equal to_______________?

1.50 hw

98 - Fresh sewage is generally_____________________?

Alkaline

99 - Fresh sewage may become stale in_________________?

Three to four hours

100 - Generally the weir is aligned at right angles to the direction of the main river current because______________?

all of the above

101 - Hazen's formula VS = 418 (GS – Gw)d [(3T + 70)/100] is used for the settlement velocity of the particles of diameter______________________?

Greater than 0.1 mm

102 - Horizontal acceleration due to earthquake results in______________?

both (A) and (B)

103 - Hydraulic mean radius is_______________?

Cross-sectional area/wetted perimeter

104 - hydraulically equivalent, the relationship which holds good, is _______________?

D8/3 = 4 b8/3

105 - Hydrodynamic pressure due to earthquake acts at a height of_________________?

4H/371 above the base

106 - If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is_________________?

400 mg/l

107 - If a paper moistened with lead acetate for five minutes when placed in manhole turns black. The sewer certainly contains__________________?

Hydrogen sulphide

108 - If D is the depth of scour below original bed, then the width of launching apron is generally taken as________________?

1.5 D

109 - If d is the depth of the aquifer through which water is flowing, then the relationship between permeability k and transmissible T is given by_______________?

T = kd

110 - If D is the diameter of a circular sewer and D' is the top horizontal diameter of an equivalent egg shaped section, the relationship which holds good, is_______________?

D' = 0.84 D

111 - If D.O. concentration falls down to zero in any natural drainage, it indicates the zone of__________________?

Active decomposition

112 - If four fires break out in a city of population 40 lakhs and if each hydrant has three streams and duration of each fire is four hours, the total quantity of water required, is______________________?

2880 kilo litres

113 - If is the diameter of upper circular portion, the area of cross-section of a standard egg shaped sewer, is____________________?

D²

114 - If is the diameter of upper circular portion, the overall depth of a standard egg shaped section, is___________________?

1.5 D

115 - If is the diameter of upper circular portion, the overall depth of New Egg shaped sewer section, Is_____________________?

1.625 D

116 - If is the rugosity coefficient, is the bed slope of sewer, the velocity of flow in m/sec may be obtained by the formula V = (1/n) r2/3 s1/2 evolved by_________________?

Manning

117 - If it rains between 2 P.M. and 3 P.M. and the entire basin area just starts contributing water at 3 P.M. to the outlet, then time of concentration will be_____________________?

60 minutes

118 - If q is the average sewage flow from a city of population P, the maximum sewage flow______________?

Q = [(18 + )/(4 + )] q

119 - If the critical shear stress of a channel is xc, then the average value of shear stress required to move the grain on the bank is___________________?

0.75 TC

120 - If the demand line drawn from a ridge in a flow mass curve does not intersect the curve again, it indicates that______________?

demand cannot be met by inflow

121 - If the depth of flow in a circular sewer is 1/4th of its diameter D, the wetted perimeter is______________?

/3

122 - If the depth of partial flow in a sewer of diameter 2 m, is 50 cm, its wetted perimeter is____________________ ?

44960

123 - If the diameter of a sewer is 100 mm, the gradient required for generating self cleansing velocity is__________________?

1 in 60

124 - If the diameter of a sewer is 150 mm, the gradient required for generating self cleansing velocity, is________________?

1 in 100

125 - If the diameter of sewer is 225 mm, the gradient required for generating self cleansing velocity, is___________________?

1 in 120

126 - If the discharge of a sewer running half is 628 1.p.s., i = 0.001, and n = 0.010, the diameter of the sewer, is__________________?

1.69 m

127 - If the flame of a miner's safety lamp in a manhole extinguishes within 5 minutes, the sewer certainly contains_______________?

Carbon dioxide

128 - If the flame of a miner's safety lamp in the upper layers of the sewer forms an explosive, the sewer certainly contains_______________?

Methane

129 - If the grit in grit chambers is 4.5 million litres per day, its cleaning is done____________________?

Manually

130 - If the intensity of rainfall is more than the infiltration capacity of soil, then the infiltration rate will be______________?

equal to infiltration capacity

131 - If the length of overland flow from the critical point to the mouth of drain is 13.58 km and difference in level between the critical point and drain mouth is 10 m, the inlet time is___________________?

8 hours

132 - If the over land flow from the critical point to the drain is 8 km and the difference in level is 12.4 m, the inlet time is________________?

4 hours

133 - If the peak discharge of a storm water drain (S.W. Drain) is expected to exceed 150 cumecs, the free board to be provided, is_________________?

100 cm

134 - If the pH value of sewage is 7__________________?

It is neutral

135 - If the R.L's of canal bed level and high flood level of drainage are 212.0 m and 210.0 m respectively, then cross drainage work will be________________?

syphon

136 - If the risk of a flood occurring in the next 10 years is accepted to 10%, then the return period for design should be__________________?

1/(1-0.9°10)

137 - If the side of a square sewer is 1000 mm, the diameter of a hydraulically equivalent circular section, is___________________?

1095 mm

138 - If there are two canals taking off from each flank of a river, then there will be____________________?

two divide walls and two undersluices

139 - Imhoff cone is used to determine_____________________?

Settleable solids

140 - Imhoff cone is used to measure________________?

Settleable solids

141 - In 1000 kg of sewage, the total solids approximate___________________?

0.5 to 1.0 kg

142 - In a chute spillway, the flow is usually____________________?

super critical

143 - In a city the ratio of the drainage to sewage is 20, the percentage discharge passing through non-monsoon periods, is_____________________?

20

144 - In a fully mechanised composting plant, involves________________?

All of these

145 - In a grit chamber of a sewage treatment plant ____________________?

All the above

146 - In a residential colony, sewers of diameters 100 mm, 150 mm and 225 mm were laid with a gradient 1 in 120. Which portion of the sewage system does not choke in due course of time?

225 mm dia.

147 - In a Sarda type fall, rectangular crest is used for discharge upto______________?

14 cumecs

148 - In a sedimentation tank (length L, width B, depth D) the settling velocity of a particle for a discharge Q, is____________________?

Q/(B × L)

149 - In a sludge digestion tank if the moisture content of sludge V1 litres is reduced from p1 % to p2 % the volume V2 is____________________?

[(100 – P1)/(100 – P2)] V1

150 - In a sludge tank, the gas mainly produced, is_________________?

Carbon dioxide

151 - In a trickling filter_________________?

Biological action is used

152 - In areas where light rains are uniformly distributed throughout the year, the type of sewerage system to be adopted is_______________?

Combined system

153 - In areas where rainy season is limited to a few months, the type of sewerage system recommended is__________________?

Separate system

154 - In case of Imhoff tanks_____________________?

All the above

155 - In case of non-availability of space due to topography, the most suitable spillway is________________?

shaft spillway

156 - In case of sewer lines_________________?

All the above

157 - In Chezy's formula V = C rs for calculating the velocity of flow in circular sewer of diameter running full, the value of hydraulic mean radius is_______________?

D/4

158 - In circular sewers if depth of flow is 0.2 times the full depth, the nominal gradient,______________?

Is doubled

159 - In detritus tanks______________________?

All the above

160 - In distribution pipes, drain valves are provided at_______________?

lower point

161 - In normal conditions, the period for sludge digestion, is_______________?

30 days

162 - In olden days the type of section adopted in trunk and out fall sewers was__________________?

Horse shoe shaped

163 - In primary sedimentation, the 0.2 mm inorganic solids get separated if specific gravity is_________________?

2.65

164 - In septic tanks, decomposition of organic bacteria, is done by_____________________?

Anaerobic bacteria

165 - In septic tanks__________________?

All the above

166 - In sewage having fully oxidised organic matter, the nitrogen exists in the form of________________?

Nitrates

167 - In sewage, the solids in mg per litre is__________________?

500 to 1000

168 - In sewers designed with self cleansing velocity________________?

Neither silting nor scouring occurs at the bottom

169 - In sewers the effect of scouring is more on__________________?

Bottom side

170 - In sewers the gas generally found, is_________________?

All the above

171 - In sewers the highest non-scouring velocity is achieved in________________?

Glazed bricks sewers

172 - In sewers the velocity of flow should not be_________________?

Less than the self-cleansing velocity

173 - In SI units the power of sound is represented in __________________?

Watts

174 - In the activated sludge process__________________?

Aeration is done with an admixture of previously aerated sludge

175 - In very first stage of decomposition of the organic matter in sewage________________?

Ammonia is formed

176 - Infiltration capacity_________________?

changes with both time and location

177 - Infiltration rate is always________________?

equal to or less than the infiltration capacity

178 - Inter-distance between ventilation columns in a sewer line is kept__________________?

150 m to 300 m

179 - Irrigation water having the concentration of Na++ , Ca++ and Mg++ as 20, 3 and 1 Milli equivalent per litre respectively will be classified as__________________?

medium sodium water

180 - It is customary to design a sewer for D.W.F. on the basis of________________?

Thrice the average demand

181 - Kjeldahl nitrogen is a mixture of___________________?

All the above

182 - Large diameter sewers subjected to external pressure alone, are reinforced ______________________?

With elliptical cage

183 - Lead acetate test in sewer manhole is done to test the presence of ____________________?

Hydrogen sulphide

184 - Lead caulked joints are used for laying____________________?

Earthenware pipes

185 - Lining of irrigation channels________________?

decreases the waterlogging area

186 - Main purpose of mean water training for rivers is________________?

to preserve the channel in good shape by efficient disposal of suspended and bed load

187 - Maximum permissible velocity 1.5 m/sec, is adopted in drains_______________________?

Both A. and B.

188 - Nitrogen cycle of sewage, is____________________?

Liberation of ammonia-formation of nitrites-formation of nitrates-liberation of nitrogen

189 - Oxidation process results in the formation of___________________?

All the above

190 - Pathogens (or pathogenic bacterias) in water may cause___________________?

All the above

191 - pH value of sludge during alkaline regression stage, is__________________?

More than 7

192 - Pick up the correct statement from the following ?

All of these

193 - Pick up the correct statement from the following ?

All of these

194 - Pick up the correct statement from the following ?

All the above

195 - Pick up the correct statement from the following ?

All the above

196 - Pick up the correct statement from the following ?

All the above

197 - Pick up the correct statement from the following ?

The larger the sewer in size, deposition will take place

198 - Pick up the correct statement from the following ?

All the above

199 - Pick up the correct statement from the following _________________?

All the above

200 - Pick up the correct statement from the following?

All of these

201 - Pick up the correct statement from the following?

All of these

202 - Pick up the correct statement from the following?

An increase of phytoplankton decreases the back scattering in the green region

203 - Pick up the correct statement from the following?

All the above

204 - Pick up the correct statement from the following?

The water supply pipes carry pure water free from solid particles

205 - Pick up the correct statement from the following?

All the above

206 - Pick up the correct statement from the following?

All the above

207 - Pick up the correct statement from the following?

All the above

208 - Pick up the correct statement from the following?

All the above

209 - Pick up the correct statement from the following?

all of these

210 - Pick up the correct statement from the following?

All the above

211 - Pick up the correct statement from the following?

All the above

212 - Pick up the correct statement from the following?

All the above

213 - Pick up the incorrect size of stone ware sewers_________________?

None of these

214 - Pick up the incorrect statement from the following ?

None of these

215 - Pick up the incorrect statement from the following for allowing workers to enter sewers_______________?

The men entering the manhole should be advised to smoke in the sewer

216 - Pick up the incorrect statement from the following?

The old convergence system was definitely better than water carried sewerage system

217 - Pick up the incorrect statement from the following?

The gases produced in sludge digestion process, contain 75% carbon dioxide

218 - Pick up the in-correct statement from the following?

Inlets are generally provided in all sewers

219 - Primary treatment of sewage consists of removal of__________________?

Large suspended organic solids

220 - R.M.O. expenses include___________________?

All the above

221 - Rate of flow of sewage is generally assumed__________________?

At 150 litres per capita

222 - Removal of oil and grease from sewage, is known____________________?

Skimming

223 - River training for depth is achieved by_______________?

groynes and bandalling

224 - running partially full with central angle , For a circular sewer of diameter__________________?

All the above

225 - Seepage through embankments in an earthen dam is controlled by_______________?

drain trenches

226 - Seepage through foundation in an earthen dam is controlled by providing___________________?

impervious cut off

227 - Self-cleansing velocity is__________________?

Velocity at which no accumulation remains in the drains

228 - Setting out the alignments of sewers may start from__________________?

Tail end

229 - Sewer manholes are generally provided at________________?

All of these

230 - Sewer pipes are designed for maximum discharge with 25% to 33% vacant cross-sectional area for__________________?

All of the above

231 - Sewer pipes need be checked for_________________?

Both A. and B.

232 - Sewer ventilating columns are generally placed at_______________?

All the above

233 - S-hydrograph is used to obtain unit hydrograph of________________?

both (A) and (B)

234 - Silt excluders are constructed on the________________?

river bed upstream of head regulator

235 - Skimming tanks are__________________?

Used to remove the grease and oil

236 - Sludge banks are formed if sewage is disposed of in____________________ ?

Seas

237 - Stone ware pipes are_______________?

Especially suited to pressure pipes

238 - Sunlight_________________ ?

impedes growth of algae

239 - Surge tanks are used_______________?

to guard against water hammer

240 - The “outlet discharge factor” is the duty at the head of_________________?

watercourse

241 - The algae dies out in the zone of_____________________?

Degradation

242 - The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known_________________?

Dissolved Oxygen (D.O.)

243 - The angle subtended by the surface of sewer water with partial flow, at sewer centre is 120°, the depth of sewerage is________________________?

50 cm

244 - The aqueduct or superpassage type of works are generally used when_______________?

high flood drainage discharge is small

245 - The area between the isohyets 45 cm and 55 cm is 100 square km and between 55 cm and 65 cm is 150 square km. The average depth of annua! precipitation over the above basin of 250 square km will be__________________?

56 cm

246 - The arrangement made for passing the sewer line below an obstruction below the hydraulic gradient lines called ____________________?

all of these

247 - The asbestos cement pipes are generally laid___________________?

Vertically

248 - The best unit duration of storm for a unit hydrograph is________________?

one-fourth of basin lag

249 - The bottom of the sewage inlet chamber of septic tanks, is provided an outward slope_________________?

1 in 10

250 - The Chezy's constant C in the formula V = C_________________?

All the above

251 - The clarigesters are_________________?

Circular Imhoff double storey tanks without bottom hoppers

252 - The coagulant which is generally not used for treating the sewage, is__________________?

Alum

253 - The coagulant widely used for sewage treatment, is_________________?

Ferric chloride

254 - The density of population over 40 hectares is 250/hectare. If water supply demand per day is 200 litres and sewage discharge is 80% of water supply, the sewage flow in sewers of separate system, is_____________________?

0.05556 cumec

255 - The design period in years for pumping plants, is___________________?

5 to 10

256 - The design period of sewage treatment works in normally_________________?

15 – 20 years

257 - The detention period for plain sedimentation water tanks, is usually____________________?

4 to 8 hours

258 - The detention time (t) of a settling tank, may be defined as the time required for_________________?

The flow of sewage to fill the tank

259 - The detention time of a circular tank of diameter d and water depth H, for receiving the sewage Q per hour, is________________?

d² (0.011d + 0.785H)/Q

260 - The digested sludge from septic tanks, is removed after a maximum period of__________________?

3 years

261 - The dimensions of a rectangular settling tank are: length 24 m, width 6 m and depth 3 m. If 2 hour detention period for tanks is recommended, the rate of flow of sewage per hour, is_____________________?

216 cu.m

262 - The discharge per unit plan area of a sedimentation tank, is generally called________________?

All the above

263 - The disintegrating pump in which solid matter is broken up before passing out, is__________________?

Centrifugal pump

264 - The drainage area of a town is 12 hectares. Its 40% area is hard pavement ( K = 0.85), the 40% area is unpaved streets (K = 0.20) and the remaining is wooded areas (K = 0.15). Assuming the time of concentration for the areas as 30 minutes and using the fo

0.15 cumec

265 - The drainage water intercepting the canal can be disposed of by passing the canal below the drainage in___________________?

super passage and canal syphon

266 - The drop man holes are generally provided in sewers for____________________?

Hilly town ships

267 - The effluent of a septic tank is_________________?

Fit for discharge into any open drain

268 - The expected discharge to be obtained from an open well sunk in coarse sand is 0.0059 cumec. If the working depression head of the well is 3 m, the minimum diameter of the well, is________________?

3.00 m

269 - The factor responsible for purification of sewage in river is________________?

All the above

270 - The fire demand of a city may be worked out by _________________?

All the above.

271 - The first stage of neutral process of sludge digestion, is__________________?

Acid fermentation

272 - The flow of water after spilling over the weir crest in chute spillway and side channel spillway respectively are_________________?

at right angle and parallel to weir crest

273 - The flow velocity in detritus tanks is________________?

0.09 m/sec

274 - The flow-mass curve is graphical representation of__________________?

cumulative discharge, volume and time in chronological order

275 - The following is the physical characteristic of sewage___________________?

All the above

276 - The formula V = (1/n) r2/3____________________?

Manning's formula

277 - The formula which accepts the value of rugosity coefficient n = 0.012 to be used in Manning's formula, is given by______________________?

Crimp and Bruges

278 - The gas evolved in sewers is________________?

All of these

279 - The gas which may cause explosion in sewers, is_________________?

Methane

280 - The gradient of sewers depends upon_________________?

All the above

281 - The grit and silt of the grit chambers, may not be used for_________________?

Concreting

282 - The grit chambers of sewage treatment plants, are generally cleaned after__________________?

14 days

283 - The intensity of rain is expressed in________________?

cm/hour

284 - The layers of vegetable wastes and night soil alternatively piled above the ground to form a mound, is called_______________?

None of these

285 - The laying of sewers is done with____________________?

Level

286 - The least thickness of class B cast iron (spun) pipe, is_________________?

8.6 mm

287 - The liquid wastes from kitchens, bath rooms and wash basins, is not called________________?

Sewage

288 - The main cause of meandering is________________?

the extra turbulence generated by the excess of river sediment during floods

289 - The main function of a divide wall is to_______________?

separate the undersluices from weir proper

290 - The major resisting force in a gravity dam is___________________?

self-weight of dam

291 - The maximum depth of sedimentation tanks, is kept__________________?

3 m

292 - The maximum diameter of sewers adopted in the designs is_______________?

3.0 m

293 - The maximum permissible eccentricity for no tension at the base of a gravity dam is__________________?

B/6

294 - The maximum rainfall depth of 300 mm in 24 hours has a return period of 100 years. The probability of 24 hours rainfall equal to or greater than 300 mm occurring at least once in 10 years is given by_____________?

1 – (0.99)10

295 - The maximum spacing of manholes specified by Indian standard in sewers upto 0.3 m diameter is____________________?

45 m

296 - The meander pattern of a river is developed by_________________?

dominant discharge

297 - The minimum diameter of a sewer is kept __________________?

15 cm

298 - The minimum diameter of sewer to be adopted is_________________?

15 cm

299 - The minimum recommended diameter of sewers, is_________________?

15 cm

300 - The minimum size of stone that will remain at rest in a channel of longitudinal slope S and hydraulic mean depth R is given by______________?

11 RS

301 - The moisture content of sludge is reduced from 90% to 80% in a sludge digestion tank. The percentage decrease in the volume of sludge, is_______________?

0.5

302 - The most dangerous pollutant in vehicular emissions is____________________?

CO

303 - The most effective arrangement for diverting excess storm water into a natural drainage, is____________________?

Siphon spill way

304 - The most efficient cross section of sewers in a separate sewerage system is__________________?

Circular

305 - The most efficient cross-section of sewers in a combined sewerage system is________________?

Circular

306 - The most suitable material for the central impervious core of a zoned embankment type dam is_______________?

clay mixed with fine sand

307 - The most widely used pump for lifting sewage is_________________?

Centrifugal pump

308 - The net head under which the turbine reaches its peak efficiency at synchronous speed is called________________?

design head

309 - The net speed under which the turbine reaches its peak efficiency is called_________________?

design speed

310 - The non-clog pump which permits solid matter to pass out with the liquid sewage, is________________?

Centrifugal pump

311 - The normal annual precipitation at stations X, A, B and C are 700 mm, 1000 mm, 900 mm and 800 mm respectively. If the storm precipitation at three station A, B and C were 100 mm, 90 mm and 80 mm respectively, then the storm precipitation for station X wil

70mm

312 - The normal value of over flow rates for plain primary sedimentation tanks, ranges between________________?

40,000 to 50,000 litres/sqm/day

313 - The normal values of over flow rates for secondary sedimentation tanks, ranges between__________________?

25,000 to 35,000 litres/sqm/day

314 - The normal values of over flow rates for sedimentation tanks using coagulant, ranges between__________________?

50,000 to 60,000 litres/sqm/day

315 - The peak of a 4 hour flood hydrograph is 240 m3/sec . If the rainfall excess is 80 mm and base flow which is constant is 40 m3/sec, then the peak of 4-hours unit hydrograph will be__________________?

25 m3/sec

316 - The pH value of fresh sewage is usually ______________________?

More than 7

317 - The pH value of sewage is determined with the help of_________________?

Potentiometer

318 - The porosity of sediments in sewer pipes, is usually taken as___________________?

0.013

319 - The presence of free ammonia in sewage, is detected by___________________?

Boiling

320 - The quantity of liquid waste which flows in sewers during the period of rainfall, is known__________________?

Storm sewage

321 - The rainfall at any place may be determined by__________________?

All the above

322 - The rainfall on five successive days were measured as 100 mm, 80 mm, 60 mm, 40 mm and 20 mm respectively. If the infiltration index or the storm loss rate for the catchment area is earlier estimated as 50 mm/day, the total surface run off will be_________

90 mm

323 - The rate of accumulation of sludge in septic tanks is recommended as____________________?

30 litres/person/year

324 - The rate of accumulation of sludge per person per year, is_______________________?

20 litres

325 - The ratio of average values of shear stresses produced on the bed and the banks of a channel due to flowing water is________________?

greater than 1

326 - The ratio of design discharge to the surface area of a sedimentation tank is called____________________?

All of these

327 - The ratio of maximum sewage flow to average sewage flow for mains up to 1 m in diameter, is___________________?

2

328 - The ratio of maximum sewage flow to average sewage flow for trunk mains having diameters more than 1.25 m, is____________________?

1.5

329 - The ratio of minimum hourly flow to the average flow of sewage is_________________?

44929

330 - The ratio of rate of change of the discharge of an outlet to the rate of change of the discharge of distributing channel is called________________?

flexibility

331 - The ratio of the diameter of a circular section and the side of a square section hydraulically equivalent, is____________________?

1.095

332 - The rational formula for peak drainage discharge, was evolved by_________________?

All of these

333 - The recommended detention period for grit chambers is_______________?

1 minute

334 - The reduced levels of the string at the consecutive sight rails A and B are 203.575 m, 203.475 m respectively. If the difference of their R.D.s is 10 m, the gradient of the sewer line is_________________?

1 in 100 downward

335 - The relation between probability (P) and recurrence interval (T) is given by_________________?

PT = 1

336 - The runoff increases with________________?

increase in intensity of rain

337 - The screens are fixed___________________?

At an angle 30° to 60° to the direction of flow

338 - The self-cleansing velocity of water flowing through pipe lines, is___________________ ?

2 metres/sec

339 - The sensitivity of a rigid module is_______________?

zero

340 - The settlement of a particle in sedimentation tank, is affected by_____________________?

All the above

341 - The settlement velocity of a solid (diameter 0.5 mm, specific gravity 1.75) in water having temperature 10°C, is______________________?

313.5 cm/sec

342 - The settling velocity of a spherical particle of diameter less than 0.1 mm as per Stock's law, is__________________?

Vs = 418 (Gs – Gw)d² [(3T + 70)/100]

343 - The settling velocity of the particles larger than 0.06 mm in a settling tank of depth 2.4 is 0.33 m per sec. The detention period recommended for the tank, is____________________?

2 hours

344 - The sewage discharge in a detritus tank of a treatment plant is 576 litres/sec with flow velocity of 0.2 m/sec. If the ratio of width to depth is 2, the depth is____________________?

120 cm

345 - The sewage is pumped up_______________?

All the above

346 - The sewage treatment in septic tanks is due to__________________?

Anaerobic decomposition

347 - The sewage treatment units in which anaerobic decomposition of organic matter is used, are called________________?

Trickling filters

348 - The sewer pipe which carries sewage from a building for immediate disposal is______________?

House sewer

349 - The sewer pipes__________________?

All the above

350 - The sewer that unloads the sewage at the point of treatment is called_________________?

Outfall sewer

351 - The sewer which collects the discharge from a collecting system and delivers it to a treatment plant, is known_____________________?

Sewer outfall

352 - The sewer which received discharge from two or more main sewers, is known as_______________?

A trunk sewer

353 - The sewer which transports the sewage to the point of treatment, is called________________?

Out-fall sewer

354 - The sewerage system consists of______________________?

All of these

355 - The sewerage system originates from__________________?

House sewers

356 - The sewers___________________?

All the above

357 - The shape of recession limb of a hydrograph depends upon________________?

basin characteristics only

358 - The sludge does not contain waste water from_________________?

Toilets

359 - The small sewers are cleaned by____________________?

Flushing

360 - The spacing of bars for perforations in coarse screens used for the treatment of sewage, is ____________________?

50 mm

361 - The spacing of bars of perforations of fine screens used for the treatment of sewage, is_______________?

2 to 3 mm

362 - The spacing of man holes along a straight portion of a sewer is 300 m, the diameter of the sewer may be__________________?

> 1.5 m

363 - The stage of river carrying a discharge of Q m7sec at a point is 10 m and slope of water surface is (1/4000). The discharge of a flood at the same point and same stage of 10 m with a water surface slope of(l/1000) will be________________?

2 Q m3/sec

364 - The stone ware sewers_________________?

All the above

365 - The stream which does not have any base flow contribution is called________________?

ephemeral stream

366 - The suitable cross-section of sewers to carry combined flow, is__________________?

Egg shaped

367 - The temperature affects the________________?

All the above

368 - The total capacity of a reservoir is 25 million cubic metres and dead storage is 5 million cubic metres. If the average volume of sediment deposition is 0.10 million cubic metre per year, then the usefulness of the reservoir will start reducing after_____

50 years

369 - The underground sewers are more subjected to________________?

Compressive force

370 - The unit hydrograph due to a storm may be obtained by dividing the ordinates of the direct runoff hydrograph by_______________?

direct runoff volume

371 - The unit hydrograph of a specified duration can be used to evaluate the hydrograph of storms of_________________?

any duration

372 - The uplift pressure on the face of a drainage gallery in a dam is taken as_________________?

two-third of hydrostatic pressure at toe plus one-third of hydrostatic pressure at heel

373 - The use of coarse screens for the disposal of sewage, may be dispensed with by______________?

Both A. and B.

374 - The useful storage is the volume of water stored in the reservoir between________________?

minimum pool level and normal pool level

375 - The value of Chezy's constant C = 157.6/(1.81 + K/ ) is used in__________________?

Bazin's formula

376 - The value of Sodium Absorption Ratio for high sodium water lies between________________?

18 to 26

377 - The water carried sewerage system removes__________________?

All the above

378 - The water stored in the reservoir below the minimum pool level is called_______________?

dead storage

379 - The water utilizable by plants is available in soils mainly in the form of________________?

capillary water

380 - The width of a rectangular sewer is twice its depth while discharging 1.5 m/sec. The width of the sewer is______________?

1.36 m

381 - The width of a settling tank with 2 hour detention period for treating sewage 378 cu m per hour, is __________________?

7 m

382 - The yield of a rapid gravity filter as compared to that of slow sand filter, is__________________?

30 times

383 - Time of concentration________________?

time taken for the storm water to travel from the most remote point to the drain

384 - To maintain aerobic biological activity, the moisture content of the compost mass should be about_________________?

0.55

385 - To prevent settling down of sewage both at the bottom and on the sides of a large sewer, self-cleaning velocity recommended for Indian conditions, is_________________?

0.75 m/sec

386 - To test chemical oxygen demand (C.O.D.) of sewage, organic matter is oxidised by potassium dichromate in the presence of_______________?

Sulphuric acid

387 - Tortuosity of a meandering river is the ratio of__________________?

curved length along the channel to the direct axial length of the river reach

388 - Trap efficiency of a reservoir is a function of_______________?

capacity/inflow ratio

389 - Traps_________________?

Are water seals which prevent the entry of foul gases

390 - Under the same conditions, which of the following shapes of water surface will give the highest rate of evaporation ?

convex water surface

391 - Unit of runoff in M.K.S. system is________________?

cubic metre/sec

392 - Ventilating shafts are provided to a sewer line at every__________________?

300 m

393 - Vertical drop fall is satisfactory for a height upto ___________?

1.5 m

394 - Water content of sewage is about___________________?

0.099

395 - weight of water, the hydraulic mean depth of the sewer and the bed slope w is the unit of the sewer, then the tractive force exerted by flowing water, is________________________?

w r S S

396 - Wetted perimeter of a regime channel for a discharge of 64 cumecs as per Lacey's theory will be_________?

38m

397 - When drainage to sewage ratio is 20, the peak dry weather flow is_______________?

Slightly less than 5% of the design discharge

398 - When surface of transpiration is submerged under water, then potential evapotranspiration is________________?

much more than evapotranspiration

399 - When the reservoir is full, the maximum compressive force in a gravity dam is produced______________?

at the toe

400 - When the upstream face of a gravity dam is vertical, then the intensity of water pressure at the water surface and at the base respectively will be_______________?

OandwII

401 - Which of the following can be used as a meter fall ?

vertical drop fall

402 - Which of the following canal outlets maintains a constant discharge ?

rigid module

403 - Which of the following canal structures is used to remove surplus water from an irrigation channel into a natural drain ?

canal escape

404 - Which of the following is a flexible outlet ?

Kennedy's gauge outlet

405 - Which of the following is a non-recording raingauge ?

Simon's raingauge

406 - Which of the following methods is used to estimate flood discharge based on high water marks left over in the past ?

slope-area method

407 - Which of the following spillways is least suitable for an earthen dam ?

ogee spillway

408 - Which of the following types of falls use parabolic glacis for energy dissipation ?

Montague type fall

409 - Which of the following types of rain gauges is used for measuring rain in remote hilly inaccessible areas ?

tipping bucket type

410 - Which one of the following gases is most significant as air pollutant ?

Sulphur-dioxide

411 - Which one of the following part of human body withstands minimum radiation ?

Ovaries/testis

412 - Which one of the following statement is correct ?

All of these

413 - Which one of the following statements is correct ?

All of these

414 - Which one of the following statements is correct ?

All the above

415 - Which one of the following statements is correct ?

All of these

416 - Which one of the following statements regarding septic tanks is wrong ?

The depth of tank is kept equal to its width

417 - Which one of the following tests is used for testing sewer pipes ?

All of these

418 - With self cleansing velocity in sewers___________________?

Neither silting nor scouring occurs at bottom

419 - With the increase in the quantity of water supplied, the yield of most crops_________________?

increases upto a certain limit and then decreases

420 - You are asked to design sewer pipes of diameters 0.4 m to 0.9 m at maximum flow, you will assume the sewer flow running at___________________?

Half full

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